Jack.



A. L. JOHNSON.

JACK.

APPLICATION FILED AUG. I8, 1915.

l ,aww Patented NOV. 7,1916.

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NETE@ STATES ALVIN L. JOHNSON,l OF WORCESTER, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO HI-LO JACK COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORA- TICN OF TEASSACHUSETTS.

Specification of' Letters Patent.

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Patented Nov. 7, i936.,

Application filed August l, 1915. Serial No. 46,185.

To ZZ whom t may concern.' l Be it known that l, ALVIN li. Jonsson, a citizen of the United States, residing at llorcester, in the county of Worcester andv can be moved in under the machine in a convenient manner even when the wheels are down in a rut so that there is very little space between the ground and the axle; in which although a screw is used` in operation, yet it is not necessary to move the mechanism along the screw by means ot the ratchet handle when the device is not in actual op base l@ and rest il for rece-ivm other part to be raised or i are connected by a parallel construction comprising four links Each ci' these links is provided with a segment 13 on one end, these segments being cast or punched out integral with the links. Each linlz is also pivoted at the other end to one of the other links. The two pivots thus provided are in the torni of studs le and l5. 'On the studs are hubs 16 and i?. A screw i8 passes freely through these hubs. The two hubs therefore are in alinement and are both pivoted to the pivot members le and l5. The stud la extends through the screw 18, thus holding it at that end. @n one of the studs i5 are fixed a bevel gear i9 and a ratchet wheel 20. A ratchet lever 2l having a double pawl 22 adapted to be held in either of its two positions by a spring 23 is pivoted on the stud l5. Engaging with the screw thread is a second bevel gear or pinion 2l. rlhis is adapted to mesh with the gear 19.

ln operation it will be clear that the hub l? can be moved along the screw until the rest llcomes substantially into a position to engage the axle or other part to be raised vor lowered. Then the gear can be screwed up on the screw in a veryexpeditious inanner until it engages the end this hub and also meshes ywith the gear The rest i then allowed to settle back until the gears come fully into mesh. rEhen, the pawl 22 having been placed in the right position, the handle 2l is oscillated and the two gears turned. This forces the hub l? to travel along the screw thread with the gear and the tour links l2 are forced to turn positivelywith each other. The gear segments keep the rest il in central position and no guide extending from the base 'l0 to the rest ll is required. Likewise when it is desired to fold it up the rest is raised which moves the gear 24 out of Contact with the gear i9 then the former is turned along the screw substantially to the end thereof. After that the rest il can be lowered to the position shown in Fig. l instantaneously;

lt will be seen that the liack can be made ci light materials andvis further lightened by the use of the gear segments instead ora a guide for the rest and that it is light, compact, and easily and rapidy ised to its operative condition or tele Q although l have illustrated nd described only a single embodiment of the invention am aware oi the tact that man;T medir" tions can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore, l do not wish to be lirn ited'to all the details oi' construction herein shown and described, but.

lWhat l do lcla-iin is l. ln a jack, the combination or a supporting base, a pair oi links pivotally suf)-` ported thereon, integral means on said links: for causing them to partake of each others movement and to rise or tall together about their pivots, a second pair oit links pivoted to the'free ends of the i'irst pair and pivotintegral with. the second pair of links for n the links on one side Vare pivoted together A K and slidably connected with the opposite causing them to move simultaneously in' opposite directions, and means for moving the pivotal connections between the two pairs of links toward or from each other 'to raiseor lower the rest.

`2. In a jack, the combination of a supporting base, a pair of links pivotally supported thereon, a second pair of links porting base, two pairs of links pivotedV together to form a parallelogram, means integral with certain of said links for causing the two on one side to move with those on the other side of the base, but to move oppositely, a rest at the top connected with the links, and means for directly forcing said links toward or from each other at the center to raise or lower the rest.

4. In a jack, the 4combination of a sup porting base, two pairs of links pivoted to? ,f gether to form a parallelogram, means integral with certain of said links for causing the two on one side to move with those on the other side of the base, but to'move oppositely, a rest at the top connected with the links, a' nou-rotatable horizontal screw having a uniform thread from end to end, pivotally connected with the point at which pivotal point, la nut fitting the screwhreadsand entirely free from the slidable connection, andmeans for turning the nut.

5. a jack, lthe combination 'ofv a base, a pair. of; lln'ks pivoted thereto, a second pair of links each pivotally connected with one of the other links and pivotally c0n' nected together, a work rest carried thereby oppositethe base, a screw for forcing the connected ends of the two pairsV of links A toward or from each other, andmeans independent ofsaid screw and located on the second pair of links for causing the links of the pairs to move simultaneously andv equally.

6. In a; jack, .the combination of a base,

a pair of links pivotally mounted on said base and having integral gear segments thereon in the planes of the links meshingA with each other vwhereby each link partakes of 'the motion of the other but in an opposite direction, and means at the top of v saidV links for forcing the tops apart or together simultaneously.

7. ,In 'a jack, the combination of a base, a pair of links pivotally mounted on said base and having integral gear segments thereon meshing witheach other whereby each link partakes of the motion, of the other but in an opposite direction,y another pair of links pivoted to the top of Ithe first mentioned links, a rest above them to which the second pair of Alinks are pivoted,A said second links having gear segments integral therewith meshing with eachother under said rest, andl means at the points at which the first pair of linksare connected with the second pair for :forcing the pivotal points away from--or towa d each other to lower and'raise the rest.

8. In a jack, the combination of a supporting base, a pair of linkspivotally supported thereon, means on said links for 1causing them to partake of each others movementl and to rise or fall together about their pivots, a rest supported by said links, and means independent of the first named means for raising said links and rest.

In testimony whereof I have hereunto set my hand. v A

- ALVIN L. JOHNSON. 

